Geologic Map of the
Loving Quadrangle,
Eddy County, New Mexico
By
Pederson, Joel L.; Dehler, Carol M.
June, 2004
New Mexico Bureau of Geology and Mineral Resources
Open-file Digital Geologic Map OF-GM 077
Scale 1:24,000
This work was supported by the U.S. Geological Survey, National Cooperative Geologic
Mapping Program (STATEMAP) under USGS Cooperative Agreement 06HQPA0003
and the New Mexico Bureau of Geology and Mineral Resources.
New Mexico Bureau of Geology and Mineral Resources
801 Leroy Place, Socorro, New Mexico, 87801-4796
The views and conclusions contained in this document are those of the author and
should not be interpreted as necessarily representing the official policies,
either expressed or implied, of the U.S. Government or the State of New Mexico.
Description of map units—Loving Quadrangle
Sediment color was estimated by comparing dry sediment to Munsell Color Chart (Munsell
Color, 1994).
Hd - Human disturbed areas (Holocene) — Disturbance areas are mostly quarries and/or
dump areas that obscure the local geology.
Qal - Alluvium (Holocene) — Brown (7.5 YR 6/4), silt to sand, well sorted, subangular to
subrounded, dominantly quartz with rare lithics, occupies draws and river channels and
associated active floodplains. Little to no vegetation. Overlies or inset into all older units.
Thickness 0-2m.
Qp - Playa lake deposits (Holocene) — Fine-grained deposits in playa lake along eastern
central edge of map.
Qes - Eolian sand (Holocene) — Yellowish red (5 YR 5/8), very fine lower-fine upper, well
sorted, subangular to subrounded, quartz sand derived from reworked QTg in NE part of map
area. Forms coppice dunes, climbing dunes, and sand sheets. Typically east of the Pecos River
channel and extends ~ 1 mile eastward from the river. Also abundant in northeast part of
quadrangle where it overlies QTg. Thickness <10 m.
Qaes - Alluvial and eolian deposits (Pleistocene (?) to Holocene) — Brown (7.5 YR 6/4), silty
clay to silt to sand, well sorted, subangular to subrounded grains composed of 70% quartz and
30% carbonate and chert. Weak soil development in upper 1.25 m: upper 15 cm of soil is
massive silty clay to clayey silt, brown (7.5 YR 5/4), slightly plastic, bioturbated, effervesces
strongly, local organic film with granular soil structure; gypsiferous and calcareous concretions
decrease in abundance downward to 40 cm; prismatic structure extends down to 1.25 m. Unit
locally weathers into badlands and exhibits piping. Commonly veneers nearly all Quaternary
deposits in the map area, especially units Qagp2, Qasp2, Prv, and Prlu. Thickness ≤10 m.
Qasm1 - Alluvial sand mainstem (Pleistocene (?) to Holocene) — Light brown (7.5 YR 6/4),
silt to fine sand, subrounded to subangular, well sorted, massive, quartzose and lithic grains,
scattered pebbles and rare cobbles dispersed within matrix, rare calcic nodules and laminated
drapes of dark red mud. Surface is nearly always reworked into coppice dunes. Top of unit
forms a terrace (T1), 5 m above modern the Pecos River. Deposit is equivalent to the flume sand
in Carlsbad. May overlie or be inset into Qagm2. Thickness ≤10 m.
Qasp1 - Alluvial sand piedmont (Pleistocene (?) to Holocene) — White to pink (5 Y 8/1-5 YR
7/4), tuffaceous sand and silt with mainstem pebbles, poorly exposed, not capped by calcrete,
includes a <20 cm-thick lens of reworked white (5 Y 8/1) tephra. Inset into or capping Qa2
deposits and caps the fill-cut terrace (T2). Laterally equivalent to Qasm1. Thickness 0-2 m.
Qaspm1 - Alluvial sand piedmont (Pleistocene (?) to Holocene) — Transitional deposit
between units Qasm1 and Qasp1.
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Qagm2 - Alluvial gravel mainstem (Pleiostocene) — Pink (5 YR 7/4) to red to tan, medium
sand to pebbles and small cobbles (<12 cm diameter) in sand and gravel lenses, subangular to
well rounded, poorly to well sorted. Pebbles consist of chert, gray and maroon quartzite, and
metamorphic clasts (?); smaller cobbles include chert, quartzite, dolomite, limestone,
metamorphic schist, bull quartz, and basalt; and large pebbles and small cobbles are carbonate
lithics. Gravel becomes sandy conglomerate where well cemented by calcite. Local potholes.
Associated with a medium-light gray (2.5 Y) tephra (?) that is finely crystalline. Fine-grained
facies locally laminated. Sands and gravels are commonly crossbedded, with some imbrication.
Paleocurrent data indicate south-southeasterly flow. Capped by calcrete layer (0 - <2 m thick).
Cemented mainstem gravels make riffles/restrictions along the river channel in the southeast
corner of the quadrangle. The top of Qagm2 with potholes could be a fill-cut equivalent to T2.
A low-angle unconformity exists between Qagm2 and underlying TQg. Large irregular chunks
of gypsum (from the underlying clastic Rustler Formation) are common where Qagm2 overlies
Permian units. Thickness 0-75 m.
Qasgm2 - Alluvial sand and gravel mainstem (Pleiostocene) — Pink (5 YR 7/4) to red to tan,
medium sand with lesser pebble and small cobbles (<12 cm diameter), subangular to well
rounded, poorly to well sorted. Pebbles of chert, gray and maroon quartzite, metamorphic
clast(?),smaller cobbles are carbonates, chert, quartzite, dolomite, limestone, metamorphic,
schist, bull quartz, and basalt, large pebbles and small cobbles are carbonate lithics. Local
potholes. Associated with a med-light gray (2.5 Y) tephra (?) that is finely crystalline. Locally
laminated to trough-crossbedded, and imbrication. Paleocurrent data indicate southsoutheasterly flow. Capped by calcrete layer (0-< 2 m thick). Cemented mainstem sands and
gravels make riffles/restrictions along river channel in SE corner of quadrangle. Top of Qasgm2
with potholes could be a fill-cut equivalent to T2. Low-angle unconformity between Qasgm2
and underlying TQg. Deposit associated with big irregular chunks of gypsum (from underlying
clastic Rustler Fm) and commonly overlies Permian units. Thickness 0-75 m.
Qasgp2 - Alluvial sand and gravel piedmont (Pleistocene) — Pink to red sand and gray to
white gravel, poorly sorted, angular to subrounded. Sand composed of quartz and locallyderived limestone, dolomite, and chert. Gravels are composed of locally-derived limestone,
dolomite, and chert. Calcrete (1-2 m thick). Piedmont deposit in northeast area of map.
Thickness 0->~75 m.
Qasp2 - alluvial sand piedmont (Pleistocene) — Pink to red sand, poorly sorted, angular to
subrounded, composed of quartz, and locally-derived limestone, dolomite, and chert. Calcrete
(1-2 m thick). Piedmont deposit in northeast area of map. Thickness 0 - >~75 m.
Qagpm2 - Alluvial gravel piedmont and mainstem (Pleiostocene) — Transitional deposit
between units Qasgp2 and Qagm2.
Qasgpm2 - Alluvial sand and gravel piedmont and mainstem (Pleistocene) — Transitional
deposit between units Qasgp2 and Qasgm2.
QTg - Gatuna Formation (late Tertiary to early Pleistocene?) — Moderate orange pink (5
YR 8/4) to reddish orange (10 R 6/6) to red (2.5 YR 5/6), well sorted, subrounded to well
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rounded siltstone to sandstone (silt to fine upper sand), calcite cemented, bluish hue in places,
locally gypsiferous, local well rounded granules and pebbles of chert, interbedded with noncalcareous mudstone (weathers blocky). Sandstone and siltstone beds are medium to thick with
horizontal planar laminations, low-angle crossbeds, and cut-and-fill structures. Mudstones are in
lenticular to tabular thin beds and also in m-scale-thick intervals. Slope former with badland
weathering. Capped by mudstone- and gravel-bearing calcrete: plug is 0.5-1.0 m thick, pillar
structures penetrate down into bedrock about 2 m. Varying bedding orientations in area indicate
local warping (salt tectonics). Forms prominent redbeds in southeast and east part of quadrangle.
Overlies Permian bedrock units. Highly variable thickness 0 - >~130 m (from cross section).
Prm - Rustler Formation, Magenta Dolomite (Ochoan) — Pinkish gray fresh, light pink
weathered (2.5 YR 6/4 to 2.5 YR 7/2), gypsiferous, sugary limestone, medium crystals (0.250.35 mm dia), poorly to moderately indurated. Very finely laminated to massive in thin beds,
laminations are planar to crinkly. Microbial buildups present in equant to elongate heads (cmscale to decimeter scale, maximum of 30 cm) with synoptic relief of mms to cms. Locally
vesicular and chicken wire weathering common. Varying bedding orientations indicate local
warping (salt tectonics). Exposed in eastern part of quadrangle and shown in cross section.
Contacts with other units were not observed. Thickness ~≤3 m.
Prc - Permian Rustler Formation, Culebra Dolomite Member (Ochoan) — Creamweathered and fresh (7.5 YR 8/1), sugary, finely crystalline, locally yellow to red to pink(10 YR
8/2), sandy limestone. Low-angle crossbeds, planar horizontal laminations to massive in thin to
thick tabular beds (< 0.75 m thick). Vesicles follow bedding, hematite present near vesicles and
along laminations, auto-brecciated locally, some recessive interbeds where gypsum and (or)
mudstone has locally been removed. Vertical and horizontal joints filled with gypsum and
calcite, gypsum crystals in vugs, chicken-wire weathering in cm, decimeter, and meter scales.
Capped by 1-2 m of calcrete. Exposed in Culebra bluffs area where it is folded into broad
synclines and anticlines. Riffles and channel restrictions associated with bedrock exposures of
this unit in the area of Herradura Bend and Culebra Bluffs. Thickness ~≤20 m (from cross
section).
Prv - Rustler Formation Virginia Draw Member (Ochoan) — Deep orange-red weathered
and fresh (10R 4/6) and locally green to gray (GLEY 7/10 Y), siltstone to very fine lower to
medium lower sandstone, with rare coarse grains, moderately well sorted, subangular to round,
interbedded with gypsiferous green-red claystones and mudstones. Medium beds of silty
sandstones interbedded with very thin beds of greenish gypsiferous claystone and mudstone,
massive, finely laminated to medium bedded, wavy bedding and ripples crossbeds. Highly
contorted into micro- and mesoscale folds, highly fractured with gypsum veins, and fractured
into intraclastic breccia. Capped by 1-2 m thick calcrete. Weathers into badlands. Exposed in
irrigation ditches in southwest part of quadrangle—good area to characterize lower siliciclastic
Vdraw member(?) of Rustler Member. Base of unit not exposed. Thickness ~130 m (from cross
section).
Prlu - Ruster Formation lower undifferentiated (Ochoan) — Irregular masses of gypsum,
dolomite (Prc), and salt in large blocks scattered on surface and outcrops with chaotic bedding
orientations. Exposed in eastern and southern part of quadrangle. Associated with yellow ripple-
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cross-laminated sandy dolomite blocks and massive gypsum blocks at surface in Gypsum Bend
area. May include upper Salado Formation. Thickness unknown.
Pru - Rustler Formation undifferentiated (Ochoan) — Irregular masses of gypsum,
dolomite(Prc and Prm), and salt in large blocks scattered on surface and outcrops with chaotic
bedding orientations. Exposed in eastern part of quadrangle. Highly contorted with overlying
QTg by railroad cut east of factory. May include upper Salado Formation. Thickness unknown.
Ps - Permian Salado Formation (Ochoan) — In cross section only. Halite and anhydrite with
subordinate potash salts, dolmite to silty-sandy dolomite, and claystone to siltstone. Thins to
southwest. (550-650 m thick).
Pc - Permian Castille Formation (Ochoan) — In cross section only. Anhydrite and
interbedded halite. Thickness ~60-100 m.
Pl - Permian Delaware Mountain Group, Bell Canyon Formation, Lamar Limestone
Member (Ochoan- Guadalupian) — In cross section only. Limestone, siltstone, and possibly
sandstone and shale. Thickness ≤0-15 m.
Pd - Permian Delaware Mountain Group, undifferentiated (Guadalupian) — In cross
section only. Sandstone, siltstone, and shale with subordinate limestone. Thickness >350 m.
Map symbols:
Pleistocene bar-and-swale paleocurrent indicators--from air photo interpretation, only
Paleocurrent direction-arrow indicates paleoflow direction from imbrication or crossbedding
Bedding contact-dashed where approximately located or where interpreted from air photo
Basin- arrows on axis denote plunge direction
Hatchures- indicate depression made by salt removal/collapse and (or) wind deflation
Oil/gas well location
(suggested type logs for subsurface stratigraphic picks are logfile numbers 47113 or 24319)
Water well location
Depositional environments of Permian facies
Permian outcrops in the Loving quadrangle are exposed along the Pecos River and in a few
places in the southern part of the quadrangle. It is difficult to characterize these units due to the
poor exposure and the contorted nature of the strata. Sedimentary structures are rare and
macrofossils were not found during this study. The sedimentary characteristics of the Culebra
and Magenta dolomites suggest a restricted shallow shelf environment. The lower Rustler
Formation (Virginia Draw Member) also likely represents a restricted low-energy environment.
The Virginia Draw Member is nicely exposed in irrigation ditches in the southwest part of the
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Loving quadrangle. This is a good area to characterize the lower siliciclastic Virginia Draw
Member(?) of Rustler Formation.
Structural geology
The structural history of this quadrangle is difficult to interpret based on limited exposure of
bedrock units. The cross section and map, although very crude, reflect gentle folding of the
Permian units, although bedding orientation is not well established. Laramide reactivation of
late Paleozoic structures and (or) deformation from salt tectonics are two viable scenarios (Hiss,
1976c), however salt tectonics is favored because deformation does not appear to propogate
downward through the strata (see Culebra Bluffs area of cross section). Additionally, the random
orientation of much of the bedding, and the presence of domes and basins in the area, suggest
that salt mobility has been, in part, responsible for local deformation of bedrock units. Varying
bedding orientations and convolution of all pre-Holocene deposits suggest that salt tectonics has
been active as late as mid-Pleistocene(?) time.
Geomorphology and landscape evolution of the Pecos River
The Gatuna Formation likely represents the earliest Pecos River deposits and may be older than
mid-Pleistocene, but is likely post Ogallala Fm. The Gatuna Formation represents a north- to
south-directed river system that underwent a significant valley-filling episode. This unit is not
fully within the present landscape position in that it is not confined to the modern Pecos Valley,
but parallels it in a broader region between uplands to the west and east.
Two hypotheses address the landscape position of the Quaternary deposits in the Loving
quadrangle. The preferred hypothesis is that the deposits underlying the hills in the quadrangle
(Qamg2) are the same deposit as that in the topographically lower surrounding landscape
(Qaes/Qagp2). Another hypothesis is that these deposits at higher elevations are an older deposit
and that the hills represent eroded terraces preserved in the landscape. This hypothesis is not
favored due to: insignificant differences in calcrete development; similar composition of clasts
(provenance); calcrete surfaces follow land surface; and no terrace risers observed. In keeping
with the first hypothesis, Qamg2 and related deposits are the oldest known Quaternary deposits
in the field area. They are post-Ogallala Fm (and post Gatuna Fm—TQg) and pre-modern Pecos
River, and likely represents the ancestral (Pleistocene) Pecos River in a setting analogous to the
modern Pecos River. Although most of the alluvial gravels in the quadrangle may be
approximately the same age, they may be polygenetic. There is however a notable thinning of
the calcrete layer in the SE part of the Loving quadrangle on Qasm2. This may be due to age (is
this T2?) or it may be the effect of finer material on soil development.
Aeolian deposits (Qes and Qaes) in the area are dominantly confined to the eastern side of the
Pecos River (downwind side), within about a mile of the Pecos River. The main sand source for
these dunes is from the paleo- and modern Pecos River deposits.
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References
Austin, G.S., 1978. Geology and mineral deposits of Ochoan Rocks in Delaware Basin and adjacent areas. New
Mexico Bureau of Mines and Mineral Resources, Circular 159, 88 p.
Bachman, G.O., 1984. Regional geology of Ochoan evapoites, northern part of Delaware Basin. New Mexico.
State Bureau of Mines and Mineral Resources, Circular 184, 22 p.
Boyd, D.W., 1958. Permian sedimentary facies, Central Guadalupe Mountains, New Mexico. State Bureau of
Mines and Mineral Resources, New Mexico Tech, Bulletin 49, 100 p.
Hawley, J. W., 1993. The Ogallala and Gatuna Formations in the southeastern New Mexico Region, A progress
report. In Love, D.W., Hawley, J.W., Hues, B.S., Adams, J.W., Austin, G.S., and Barker, J.M., (eds): Carlsbad
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U.S.G.S. Resource Map 7.
http://iwaters.ose.state.nm.us:7001/iWATERS/. New Mexico Office of the State Engineer [website for water data
used in cross sections].
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and Mineral Resources, Memoir 24, 78 p.
Petroleum Library at New Mexico Bureau of Geology and Mineral Resources [recource for all oil and gas well data
used in generating cross section].
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Mexico and West Texas, NMGS 44th annual field conference. pp. 271-282.
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